Age problems involve finding current ages or ages at specific times when given ratios between different people's ages. The key insight is that while individual ages change over time, age differences remain constant
๐กKey Rules
First, age difference between two people never changes. If A is 5 years older than B today, A will always be 5 years older. Second, when we add or subtract the same number of years to different ages, their ratio changes. Third, present age problems often give ratios at two different time points.
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Formula Block
Memorise โ at least one formula appears in every paper
โข If ratio of ages is a:b, then ages are ax and bx where x is common factor
โข After n years: (current age + n)
โข Before n years: (current age - n)
โข Age difference = |ax - bx| = |a - b|x
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Exam Patterns
What examiners ask โ read before attempting PYQs
SSC CGL typically asks three types - current age ratios with future/past conditions, age ratios at two different time points, and problems involving sum of ages with ratios. Questions often involve 2-3 people with time shifts of 2-10 years.
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Shortcuts
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For two-time-point problems, use the 'difference method'. If ratio changes from a:b to c:d after n years, then (cx-ax) = (dx-bx) where x is the time difference. This eliminates one variable immediately.
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Worked Example
Solve this step-by-step before moving on
1
Step 1
Let current ages be 3x and 4x
2
Step 2
After 6 years, ages become (3x+6) and (4x+6)
3
Step 3
New ratio = (3x+6):(4x+6) = 4:5
4
Step 4
Cross multiply: 5(3x+6) = 4(4x+6)
5
Step 5
15x + 30 = 16x + 24
6
Step 6
30 - 24 = 16x - 15x
7
Step 7
6 = x
8
Step 8
Current ages are 3ร6 = 18 years and 4ร6 = 24 years
Verification: After 6 years, ages are 24 and 30, ratio = 24:30 = 4:5 โ
Common Mistake: Students often forget to add/subtract years from both ages equally. Another error is setting up wrong equations when dealing with 'before' scenarios - remember to subtract years, not add them.
The ratio of ages of three friends Aman, Bimal, and Chetan is 2:3:4. If the sum of their ages is 36 years, what is Chetan's age?
Practice 2easy
The ratio of ages of Mohan and Sohan is 7:5. After 4 years, their ratio will be 9:7. What is Mohan's current age?
Practice 3easy
Ravi's age is 3/4 of Sanjay's age. If the difference between their ages is 5 years, what is Ravi's current age?
Practice 4easy
The ages of Gita and Hema are in the ratio 4:3. After 6 years, their ages will be in the ratio 6:5. What is Gita's current age?
Practice 5easy
The sum of the ages of Karan and Leela is 48 years. Their ages are in the ratio 5:3. What is the difference between their ages?
Practice 6easy
The ratio of ages of Esha and Faisal is 7:5. The difference between their ages is 8 years. What is Esha's age?
Practice 7easy
Five years ago, the ratio of Priya's age to Deepak's age was 4:5. If Deepak is currently 35 years old, what is Priya's current age?
Practice 8easy
Isha is 8 years older than Jaya. The ratio of their ages is 5:3. What is Jaya's age?
Practice 9easy
Five years ago, the ratio of Chirag's age to Deepa's age was 3:2. If Chirag is currently 20 years old, what is Deepa's current age?
Practice 10easy
The ratio of the ages of Arun and Bhavna is 5:3. If Arun is 20 years old, what is Bhavna's age?
Practice 11easy
Gita's age is twice Hema's age. Three years from now, Gita's age will be 5 years more than 1.5 times Hema's age at that time. What is Hema's current age?
Practice 12easy
The ratio of the present ages of Arun and Bhavna is 5:3. If Arun is 20 years older than Bhavna, what is Bhavna's present age?
Practice 13medium
The ratio of ages of Kavya and Neha is 7:5. Four years hence, the ratio of their ages will be 11:8. What is Kavya's current age?
Practice 14medium
The ratio of Isha's age to Jaya's age is 7:5. If the sum of their ages is 48 years, what will be Isha's age after 6 years?
Practice 15medium
Gita is currently 8 years older than Hema. In 4 years, Gita's age will be 1.5 times Hema's age. What is Hema's present age?
Practice 16medium
Five years ago, the ratio of Chitra's age to Deepak's age was 4:5. In 10 years, the ratio will be 6:7. What is Deepak's present age?
Practice 17medium
The ratio of the present ages of Arun and Bhavna is 5:3. After 6 years, the ratio of their ages will be 7:5. What is Arun's present age?
Practice 18medium
The ratio of Esha's age to Faisal's age is 3:4. If Esha is 9 years younger than Faisal, what will be the ratio of their ages after 15 years?
Practice 19medium
The ages of Rohan and Sohan are in the ratio 3:4. If the sum of their ages is 56 years, what will be Rohan's age after 8 years?
Practice 20medium
Karan's age is 2/3 of Leela's age. After 12 years, Karan's age will be 3/4 of Leela's age. What is the difference between their present ages?
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